Indigo and violet are two colors that can sometimes be confused with one another. They are close in hue and appear next to each other at the end of the visible spectrum of light. However, indigo and violet are scientifically considered distinct colors with their own specific wavelengths of light.
Definitions of Indigo and Violet
Indigo is defined as having a dominant wavelength ranging between 440-420 nanometers (nm). Violet is defined as having a wavelength between 380-450 nm. So while there is some overlap, indigo wavelengths are concentrated more towards the blue side of the spectrum while violet wavelengths are concentrated more towards the red side.
In optics, indigo’s complimentary color is yellow and violet’s complimentary color is greenish-yellow. When indigo and violet light mixes with their respective complimentary colors, the result is white light.
Origins of Indigo and Violet as Distinct Colors
Sir Isaac Newton first identified indigo as a distinct color in the 1660s when he conducted experiments separating sunlight with a prism. Newton identified seven distinct colors present in sunlight: red, orange, yellow, green, blue, indigo, and violet. This ordering of colors formed the basis for the color wheel and the mnemonic Roy G. Biv to remember the sequence of hues in the visible spectrum.
Later scientists determined that the number of distinct colors perceptible to the human eye was not fixed at seven. The boundaries between spectral colors are somewhat arbitrary and depend on how finely the spectrum is divided. However, indigo and violet remain accepted as distinct hues between blue and the invisible ultraviolet part of the spectrum.
Indigo and Violet in Art
In art and other creative fields, indigo and violet are considered separate hues with unique roles. Indigo dyes have been used since ancient times to color fabrics and other materials. The color is associated with wisdom, intuition, and perception beyond the five physical senses.
Violet has religious and spiritual symbolism, often representing mystic imagination and the striving for self-improvement or higher ideals. In healing practices like color therapy, violet light is said to have soothing, calming properties.
Having distinct indigo and violet paint pigments expanded the range of colors available on the artist’s palette. Impressionist painters like Monet, Renoir, and Seurat made great use of soft indigo and violet tones to capture subtle effects of light and shadow.
Distinguishing Indigo from Violet
So if indigo and violet are defined as separate colors, how can someone reliably tell them apart?
One way is by comparing wavelengths. As discussed earlier, indigo’s wavelength range is concentrated more towards 440-420 nm, while violet is 380-450 nm. However, for most people without spectrometers, judging color wavelengths is subjective.
A simpler approach is to look at how the colors are mixed. Indigo is mixed by combining blue and violet paint pigments. Violet is mixed using blue and red pigments. So indigo has a stronger blue hue compared to violet. Looking at the mixing recipes gives a sense of the distinct identities of each color.
| Color | Wavelength range | Mixed using |
|---|---|---|
| Indigo | 440-420 nm | Blue + violet |
| Violet | 380-450 nm | Blue + red |
The table above summarizes the differences between indigo and violet in terms of wavelength and mixing.
Appearance Differences
There are also subtle appearance differences between indigo and violet:
- Indigo has a slightly brighter, deeper blue tone compared to violet.
- Violet has more red or purple undertones compared to indigo.
- Looking closely, indigo may have a slightly greenish tint while violet appears richer and more blue-red.
However, the hue difference can be minute and difficult to discern depending on lighting conditions, material textures, and other factors. Overall indigo and violet are close enough in color that they are sometimes used interchangeably in casual conversation.
Indigo Dye and Pigments
One of the most historically significant and distinctive forms of indigo is as a dye. Indigo dye has been used to color fabrics for thousands of years. Natural indigo comes from plants such as the indigofera species and woad. When extracted and processed, these plants yield a distinctive deep blue dye.
The appeal of indigo dye comes from both its color and properties. The dye bonds strongly to fabrics through a process where the indigo molecules convert from soluble to insoluble form and attach to fabric fibers. This bonding allows the blue color to remain fast and resistant to washing and fading. The dyeing process also allows for decorative techniques like shibori tie-dyeing.
In painting, indigo pigment originally came from the same plant sources as the dye. Modern synthetic indigo pigments were created in the late 19th century. Indigo oil and watercolor pigments retain the classic indigo blue tone but with more transparency and tinting ability compared to the concentrated dye.
Violet Pigments
Violet pigments have traditionally been more difficult to produce than other colors. In ancient times, violet paint was created using minerals like manganese or grinding up precious purple gemstones. Later artisans used plant sources like lichen, mulberries, and lavender to yield dyes and pigments in violet hues.
A major historical source of violet pigment was a secretion from predatory sea snails known as murex or spiny dye-murex. These snails were cultivated by the ancient Phoenicians to produce the prized Tyrian purple dye associated with royalty and high status.
Modern violet pigments include synthetic dyes like manganese violet and quinacridone violet. These allow artists to work freely with a vivid violet color that retains its intensity over time.
Textile dyes can also create violet shades, but they tend to lack the vividness of paint pigments. Violet dyes appear more reddish and lack the blue undertones found in violet pigments specifically created for artistic use.
Conclusion
In summary, while indigo and violet can look similar, they are scientifically and artistically considered distinct colors with specific definitions:
- Indigo has a wavelength range of 440-420 nm, between blue and violet.
- Violet has a wavelength range of 380-450 nm, between blue and ultraviolet.
- Indigo has a brighter, slightly greenish blue tone compared to the more reddish violet.
- Historically, indigo and violet dyes and pigments came from different plant and mineral sources.
So while the two colors can sometimes be confused, especially in low lighting, they occupy unique places on the color spectrum. Their history, uses, and subtle appearance differences give indigo and violet their own distinct identities. Next time you come across something described as indigo or violet, take a closer look and see if you can spot the telltale differences between these two charming colors.
